#include <stdio.h>

int main()
{
    float array[10] = { 0.0f };
    float sum = 0.0f;
    float middle = 0.0f;
    for(int i = 0;i<10;i++)
    {
        scanf("%f",&array[i]);
        sum =sum + array[i];
    }
    middle = sum / 10;
    printf("%f",middle);
    return 0;
}